The present invention relates generally to compressors for providing capacity modulation. More particularly, the present invention relates to compressors for providing automatic capacity modulation without any need for external controls, a heat exchanging system including the same, and related capacity modulation methods.
Heat exchanging systems, including air-conditioning, refrigeration, and heat-pump systems, utilize compressors to increase the pressure of the fluid flowing through the systems. In response to varying cooling or heating demands, some of these heat exchanging systems modulate their system capacity by varying the capacity of the compressors. These compressors, however, typically rely on external controls for capacity modulation, and therefore, are costly because of additional components required for the external controls.
Accordingly, the present invention is directed to improved compressors for providing automatic capacity modulation. The invention is also directed to a heat exchanging system including the improved compressor, and to related capacity modulation methods. The advantages and purposes of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages and purposes of the invention will be realized and attained by the elements and combinations particularly pointed out in the appended claims.
To attain the advantages and in accordance with the purposes of the invention, as embodied and broadly described herein, the invention is directed to a variable compressor comprising a compression chamber, a reexpansion area, a flow channel, a valve member, and a control. The flow channel is between the compression chamber and the reexpansion area. The valve member is movable between first and second positions. The valve member in a first position allows flow between the compression chamber and the reexpansion area and in a second position prevents flow between the compression chamber and the reexpansion area, whereby the compressor operates at a first capacity when the valve member is in the first position and at a second, increased capacity when the valve member is in the second position. The control is associated only with the compressor and moves the valve member between the first and second positions as a function of an operating parameter of the compressor, whereby the compressor is automatically modulated based on the operating parameter.
In another aspect, the invention is directed to a compressor comprising a compression chamber, a compressing member, a flow passage, a valve member, and a biasing member. The compressing member is movable to compress fluid entering the compression chamber. The flow passage is in fluid communication with the compression chamber at one end and a reexpansion area at the other end. The valve member is associated with the flow passage and is movable between a first position permitting flow through the flow passage and a second position preventing flow through the flow passage. The valve member is continuously subjected to a first operating condition of the fluid such that a first force is continuously exerted on the valve member in a first direction. The valve member is also continuously subjected to a second operating condition of the fluid such that a second force is continuously exerted on the valve member in a second direction opposite to the first direction. The biasing member exerts a biasing force on the valve member in the second direction such that when the first force overcomes the biasing force and the second force combined together, the valve member moves from the first position to the second position and modulates the capacity of the compressor.
In yet another aspect, the invention is directed to a heat exchanging system having fluid flowing therethrough in a cycle. The heat exchanging system comprises a condenser, an expansion device, an evaporator, a compressor, and a control. The expansion device is in fluid communication with the condenser. The evaporator is in fluid communication with the expansion device. The compressor is in fluid communication with the evaporator and the condenser. The compressor includes an actuating element. The actuating element is movable between a first position and a second position as a function of an operating parameter of the compressor, such that the compressor operates at a first capacity when the actuating element is in a first position and at a second capacity when the actuating element is in the second position. The control turns the compressor on or off, based on the demand for heating or cooling.
In yet another aspect, the invention is directed to a method of operating a variable capacity compressor. The method comprises the steps of: operating the compressor at a first capacity; applying first and second pressures continuously to a movable component in the compressor, the movable component causing the compressor to operate at the first capacity when the movable component is in a first position and at a second increased capacity when the movable component is in a second position; and applying a biasing force to bias the movable component toward the first position, such that the movable component moves to the second position when the relative differential between the first and second pressures reaches a predetermined value, whereby the compressor automatically modulates its capacity based on the relative values of the first and second pressures.
In yet another aspect, the invention is directed to a capacity modulation method. The capacity modulation method comprises the steps of: providing a compressor comprising a compression chamber and a compressing member movable to compress fluid entering the compression chamber; providing a flow passage in fluid communication with the compression chamber at one end and a reexpansion area at the other end; providing a valve member associated with the flow passage and movable between a first position permitting flow through the flow passage and a second position preventing flow through the flow passage; subjecting the valve member continuously to a first operating condition of the fluid such that a first force is continuously exerted on the valve member in a first direction; subjecting the valve member continuously to a second operating condition of the fluid such that a second force is continuously exerted on the valve member in a second direction opposite to the first direction; and exerting a biasing force on the valve member in the second direction such that when the first force overcomes the second force and the biasing force combined together, the valve member moves from the first position to the second position and thereby modulates the capacity.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.